<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script type="text/javascript">
      function *show(){
        alert('a');

        yield;

        alert('b');
      }

      let gener= show();

      console.log(gener);
      gener.next();
      gener.next();
    </script>
  </head>
  <body>

  </body>
</html>
